Improvement of the detachment modelling in the SONIC simulation

Abstract In order to improve the detachment modelling, effects of various processes on ion flux reduction other than the volume recombination are investigated by using a suite of integrated divertor codes SONIC. The increase in the radial diffusion loss at the private edge decreases the ion density and the ion flux by 15% at most. The supersonic flow effect on flux reduction is small because the supersonic flow occurs just in front of the target under the present simulation condition. Due to effects of the wall pumping or D neutral recycling by hydrocarbon dissociation processes, the poloidal profile of the ion flux is significantly changed. However the change in the ion flux at the target is small. The weak rollover of the ion flux appears due to the combination of effects of the radial diffusion loss and the wall pumping.